The present invention relates to composite containers, and more particularly relates to composite containers that incorporate an electronic article surveillance (EAS) or radio frequency identification (RFID) device. These EAS and RFID devices, and other devices operating on similar principles, are generically referred to herein as electromagnetic (EM) surveillance devices.
It is becoming increasingly common for the operators of retail establishments to attach EM surveillance devices to products to deter and detect shoplifting. A number of different types of EAS tags and detector systems have been developed and are in use. Generally, all EAS systems include a detection zone formed by a transmitter and a receiver. The transmitter and receiver are positioned at the exit of the retail establishment such that consumers must pass through the detection zone in order to exit the establishment. The transmitter sends a magnetic or radio frequency signal (which are generically referred to herein as electromagnetic signals) at one or more predetermined frequencies to the receiver. When an active EAS tag enters the detection zone, the tag responds and creates a change or disturbance in the received signal, which is detected by the receiver.
One commonly used type of EAS system is the acousto-magnetic system, which utilizes a tag having a magnetostrictive metal strip that changes length in response to a changing magnetic field, and a bias magnet that biases the magnetic field so that it is never zero. The magnetostrictive metal strip is driven at its predetermined resonant frequency by a radio frequency signal generated by the transmitter at the resonant frequency (typically about 58 kHz), and in response to this driving magnetic field, the strip resonates at that frequency. The transmitter sends the RF signal in pulses, and the tag continues to resonate for a short time after the end of each pulse. The receiver detects the signals emitted by the tag in response to the RF pulses. A microcomputer in the receiver checks the tag signals to ensure they are at the correct frequency, are time-synchronized to the pulses, are at the proper level, and are at the correct repetition rate. If all these criteria are met, an alarm is sounded to alert store personnel that an article bearing a still-active EAS tag has passed in close proximity to the transmitter and receiver. The tag can be deactivated by demagnetizing the bias magnet incorporated into the tag.
Another type of EAS system is the electromagnetic system, which employs an adhesive label incorporating a wire or ribbon of metal that has a high magnetic permeability in proximity to a piece of semi-hard magnetic material. The transmitter emits a low-frequency (typically less than 1 kHz) electromagnetic field that causes the metal ribbon to become magnetically saturated twice each cycle, and the metal ribbon emits an electromagnetic signal as a result. Saturation occurs abruptly and causes distinctive patterns in the signal emitted by the label, which are detected by the receiver. The label can be deactivated by magnetizing the semi-hard magnetic material, which saturates the metal ribbon and puts it in an inactive state. The label can also be reactivated by magnetizing the semi-hard magnetic material.
The tags used in EAS systems as described above generally are not “smart” in the sense that the tags do not store information; the tags simply emit a characteristic electromagnetic signal in response to a specific driving electromagnetic field so that the presence of the tags in the detection zone can be detected. In contrast, radio frequency identification (RFID) systems employ “smart” tags that can store information and that can be remotely “read” by a reader to extract that information. Radio frequency identification systems can be used for the tracking of items through manufacturing, in inventory, in shipment, and the like. Generally, an RFID device comprises a tag that includes an integrated circuit (IC) chip microprocessor and a resonant circuit formed by a coiled antenna and a capacitor. In a passive RFID system, a reader generates a magnetic field at a predetermined frequency. When an RFID device, which usually can be categorized as being either read-only or read/write, enters the magnetic field, a small electric current forms in the device's resonant circuit. This circuit provides power to the device, which then modulates the magnetic field in order to transmit information that is pre-programmed on the device back to the reader at a predetermined frequency, such as 125 kHZ (low frequency) or 13.56 MHz (high frequency). The reader then receives, demodulates, and decodes the signal transmission, and then sends the data on to a host computer associated with the system for further processing.
An active RFID system operates in much the same way, but in an active system the RFID device includes its own battery, allowing the device to transmit data and information at the touch of a button. For example, a remote control garage door opener typically uses an active RFID device that transmits a predetermined code to the receiver in order to raise and lower the garage door at the user's discretion.
Another technology that is related to RFID is known as Bistatix, which operates much the same way as RFID devices except that the coiled antenna and capacitor of the RFID device are replaced by a printed, carbon-based material. As a result, a Bistatix device is extremely flat and relatively flexible, although currently these types of devices are limited to a frequency range of about 125 KHz. In addition, the read range of a Bistatix device is dependent on size, and for long read ranges a very large device may be required.
In the present application, the term “EM surveillance device” is used to encompass all of the above-described technologies.
Because the detection zone is actually detecting the EM surveillance device and not the good itself, the EAS system can be circumvented by removing the EM surveillance device from the good. Therefore, it is important to attach the EM surveillance devices to the goods in a manner that prevents their unauthorized removal. Some known EM surveillance devices are configured to have a closed locked position in which the EM surveillance device can not be removed without specialized equipment. These EM surveillance devices are commonly found on clothing merchandise. Other known EM surveillance devices are relatively small and thin with an adhesive backing. These EM surveillance devices are affixed to a surface of the good or product, preferably in an area that masked its presence.
Certain goods have proven challenging in terms of EM surveillance device placement. For example, goods packaged within a composite container traditionally have been difficult for effectively placing the EM surveillance device onto. Although composite containers often store inexpensive goods that typically would not be a high theft item, some relatively high cost goods, such as powdered baby formula, are stored in composite containers making these containers a high theft item and would greatly benefit from the use of an EM surveillance device. Placing an adhesive-backed device on the outside of the container is problematic because the device would be easily seen and removed. Placing the EM surveillance device into the container wall is disclosed in U.S. patent application Ser. No. 11/048,829 assigned to the same assignee as the present application, the entire contents of which are hereby incorporated by reference. However incorporating the EM surveillance device into the wall requires a capital intensive process for precision placement of the device and prevention of interference between the device and other operations of the manufacturing process. Placing the electromagnetic surveillance device between the wall and a print layer closer to the end of the process may reduce the need for precision placement. But it would decrease the aesthetics of the container by causing a bulge from the device, increase the likelihood of unauthorized removal of the device, and likely interfere with the typical convoluted print labeling process for such containers.
Furthermore, until more recently placing an EM surveillance device within the container was problematic due to the foil-based liners used within the container wall. The interference from the foil-based liners would make communication via electromagnetic signals problematic. However, composite containers without a foil layer are becoming more available, making it more practical to place EM surveillance devices within these containers. Even without the foil-based liners, placing an EM surveillance device within the container is not problem-free. For example, the inclusion of a loose EM surveillance device alone would be perceived as an undesirable foreign article or containment.
In light of the foregoing, it would be advantageous to provide a container for storing goods where the container include an EM surveillance device. In particular, it would be advantageous if the placement of the electromagnetic surveillance device is cost effective and hard to detect.